U.S. Pat. No. 3,689,935 discloses an image recording apparatus of a type provided with a toner supply portion, a back electrode and control electrodes with apertures. The toner supply portion supplies or carries charged toner particles to the control electrodes. The control electrodes are supplied with image signals to generate electric fields, degree of inclination of which is determined by the image signals. Therefore, amounts of the toner particles which are able to pass through the apertures of the control electrodes are changed according to the image signals. The back electrode also generates an electric field for further attracting toward the image receiving medium the charged toner particles which have passed the apertures of the control electrodes. Thus, amounts of the toner particles which have passed the control electrodes to reach the image receiving medium are changed according to the image signals applied to the control electrodes. Since densities of the toner particles attached on the image receiving medium correspond to the image signals, visible toner images corresponding to the image signals are formed on the image receiving medium.
In the image recording apparatus constructed as above, however, the toner particle supply portion, the control electrodes and the back electrode are fixedly mounted in the image recording apparatus at their respective portions. Therefore, in the case where either one or move of the elements get out of order, it is impossible for an operator to repair the elements or replace them with new ones. In addition, even if it is possible to replace the elements with the new ones, it takes a lot of time to arrange the elements and to regulate conditions thereof.